Trivia Question 3

Not really trivia but an interesting question nonetheless:

You are a cab driver on your way back from the annual ISSNH Appreciation Day Festival, you stop at a traffic light. Your passenger, a festive ISSNH member, is holding a helium filled balloon by the string to which it is attached. When you look back to make sure he/she is not causing any trouble, you notice the balloon is floating completely at rest, and it is not touching the roof of the car. You look back to the road, and the light then turns green.

QUESTION: As you begin accelerating, will the festive ISSNH member see the balloon tip forward, tip backwards, or not tip at all?

oh i don't know. let's say backwards (away from the driver)

if it were touching the ceiling I'd say that the friction would make the top stay relatively still while the bottom tips away making the balloon look as if it were tipping toward the driver. However, because it is not touching the ceiling I'm GUESSING it wont tip at all.

i'm guessing it won't tip at all. unless the windows are open. then you're in trouble

The balloon will burst into a giant ball of flame engulfing both passenger and driver in a hell fire that burns them into a pile of white ash in only a matter of seconds. After the fire dies down nothing will be left to question if the balloon tipped forward or not.

Tip forwards, because the air in the car will rush to the back as the car accellerates forwards.

Physics FTW.

AND THE WINNER IS:

Zarkanorg. Yes. Yes that is exactly what would happen.

THE SECOND MOST LIKELY ANSWER IS:

Pleisa. Yes, the balloon will tip forward, because like he said the air in the car will be pushed back, hence the helium balloon (which is lighter than the air) will be pushed forwards. Think about it like if the car were completely filled with water save for a single air bubble.

Another interesting way to think about it that I kind of like is to think that since the car is accelerating forwards, from inside the car it appears as if everything in the car is feeling a force towards the back of the car. Combining that force with gravity which is straight down, we then have an 'effective' gravity, which is not quite down but more tilted towards the back of the car. Hence, if you drop an object it will fall towards that direction. And since boyancy must oppose this effective gravitational force, then the string on the balloon aligns with the direction of the effective gravity in equilibrium, just as it would align with normal gravity (vertical) if the car were not moving. Hence, the new equilibrium position for the balloon is one where the string is tilted forward. TADAAAA.

Anyway. Congratulations to Zarkanorg. Pleisa, better luck next time. So to all of you who said that the balloon would go up in flames (despite that Helium is an inert gas), you guys also won. To all of you who said the balloon would tip forwards, pretty close. To all of you who said otherwise, hit the physics textbooks.

Physics FTW.

Well in my little world, stuff like that happens all the time even if your so called physics say it is impossible. I only posted that they would burn to a pile of white ash as who really cares that the balloon tipped farward. But a good science question for tripping up those that never really paid attention in class.

pshaaa - i have an english degree - i'm certainly not going back to my physics books.

it's fun when trivia returns.

And paying attention in class is only for those who went to class.

pleisa and thunderdawg am smart.
That was a good question. I liked physica, but mostly for the physicas fiar where we made a contraption that shot balls all over the place and set off walking dinos and gover crafts and such. Ours was gotham city- except for the dino- he was the Hulk

The only things I really remember from my physics class are trajectory problems, frictionless pulleys, and torque.

Versinn wrote:pleisa and thunderdawg am smart.

I see you left me out of that.

zarky am clever

if the air con was on youre all wrong cos the balloon wouldnt have been floating at all it would have been temporarily deflated on the floor...... not a physics queen, a balloon artist.... also i strongly suspect that if it was one of our bunch after a knees up it would be empty cos said reveller would be sucking it and singing silly songs in a squeeky voice like alvin and the chipmunks

Nicki wins!